The corrosion mechanism of printed circuit boards affected by haze atmospheric particles

As high-density electronic devices face increasing failure rates in polluted environments, understanding particulate-induced corrosion has become crucial. However, the combined effects of particle size, composition, and humidity on printed circuit boards (PCB) corrosion remain poorly understood. This study systematically investigates the corrosion behavior of PCB induced by atmospheric particulate matter under smog conditions. A combination of environmental sampling, compositional analysis, and controlled laboratory corrosion simulations was employed to reveal the synergistic effects of particle size, chemical composition, and humidity on the corrosion process. Particulate matter of different sizes (PM₁₀ and PM_2.5) was collected from northern China, and their morphology, ion content, and interaction with PCB-Cu surfaces were characterized using SEM, EDS, SKPFM, and Raman spectroscopy. The results show that fine particles (1-2 μm) exhibit rapid hygroscopicity and form localized electrolyte films, leading to pitting corrosion <i>via</i> oxygen concentration cells. In contrast, coarse particles (5-10 μm) absorb more moisture and induce broader but slower corrosion development. Electrochemical analysis revealed that soluble ions such as NH₄ ⁺, SO₄ ^2-, and Cl^- play dominant roles in corrosion. Specifically, Cl^- disrupts the passive film and accelerates anodic dissolution, while SO₄ ^2- and high humidity conditions promote the formation of CuO, Cu₂O, and CuSO₄·<i>x</i>H₂O. The study confirms that smog particulates facilitate a highly corrosive microenvironment through moisture uptake, ion release, and pollutant gas interaction. These findings offer mechanistic insights into particulate-induced corrosion and provide a theoretical basis for designing corrosion-resistant electronic devices and improving air quality management in industrial regions.